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1/*
2 * linux/fs/isofs/rock.c
3 *
4 * (C) 1992, 1993 Eric Youngdale
5 *
6 * Rock Ridge Extensions to iso9660
7 */
8
9#include <linux/slab.h>
10#include <linux/pagemap.h>
11
12#include "isofs.h"
13#include "rock.h"
14
15/*
16 * These functions are designed to read the system areas of a directory record
17 * and extract relevant information. There are different functions provided
18 * depending upon what information we need at the time. One function fills
19 * out an inode structure, a second one extracts a filename, a third one
20 * returns a symbolic link name, and a fourth one returns the extent number
21 * for the file.
22 */
23
24#define SIG(A,B) ((A) | ((B) << 8)) /* isonum_721() */
25
26struct rock_state {
27 void *buffer;
28 unsigned char *chr;
29 int len;
30 int cont_size;
31 int cont_extent;
32 int cont_offset;
33 struct inode *inode;
34};
35
36/*
37 * This is a way of ensuring that we have something in the system
38 * use fields that is compatible with Rock Ridge. Return zero on success.
39 */
40
41static int check_sp(struct rock_ridge *rr, struct inode *inode)
42{
43 if (rr->u.SP.magic[0] != 0xbe)
44 return -1;
45 if (rr->u.SP.magic[1] != 0xef)
46 return -1;
47 ISOFS_SB(inode->i_sb)->s_rock_offset = rr->u.SP.skip;
48 return 0;
49}
50
51static void setup_rock_ridge(struct iso_directory_record *de,
52 struct inode *inode, struct rock_state *rs)
53{
54 rs->len = sizeof(struct iso_directory_record) + de->name_len[0];
55 if (rs->len & 1)
56 (rs->len)++;
57 rs->chr = (unsigned char *)de + rs->len;
58 rs->len = *((unsigned char *)de) - rs->len;
59 if (rs->len < 0)
60 rs->len = 0;
61
62 if (ISOFS_SB(inode->i_sb)->s_rock_offset != -1) {
63 rs->len -= ISOFS_SB(inode->i_sb)->s_rock_offset;
64 rs->chr += ISOFS_SB(inode->i_sb)->s_rock_offset;
65 if (rs->len < 0)
66 rs->len = 0;
67 }
68}
69
70static void init_rock_state(struct rock_state *rs, struct inode *inode)
71{
72 memset(rs, 0, sizeof(*rs));
73 rs->inode = inode;
74}
75
76/*
77 * Returns 0 if the caller should continue scanning, 1 if the scan must end
78 * and -ve on error.
79 */
80static int rock_continue(struct rock_state *rs)
81{
82 int ret = 1;
83 int blocksize = 1 << rs->inode->i_blkbits;
84 const int min_de_size = offsetof(struct rock_ridge, u);
85
86 kfree(rs->buffer);
87 rs->buffer = NULL;
88
89 if ((unsigned)rs->cont_offset > blocksize - min_de_size ||
90 (unsigned)rs->cont_size > blocksize ||
91 (unsigned)(rs->cont_offset + rs->cont_size) > blocksize) {
92 printk(KERN_NOTICE "rock: corrupted directory entry. "
93 "extent=%d, offset=%d, size=%d\n",
94 rs->cont_extent, rs->cont_offset, rs->cont_size);
95 ret = -EIO;
96 goto out;
97 }
98
99 if (rs->cont_extent) {
100 struct buffer_head *bh;
101
102 rs->buffer = kmalloc(rs->cont_size, GFP_KERNEL);
103 if (!rs->buffer) {
104 ret = -ENOMEM;
105 goto out;
106 }
107 ret = -EIO;
108 bh = sb_bread(rs->inode->i_sb, rs->cont_extent);
109 if (bh) {
110 memcpy(rs->buffer, bh->b_data + rs->cont_offset,
111 rs->cont_size);
112 put_bh(bh);
113 rs->chr = rs->buffer;
114 rs->len = rs->cont_size;
115 rs->cont_extent = 0;
116 rs->cont_size = 0;
117 rs->cont_offset = 0;
118 return 0;
119 }
120 printk("Unable to read rock-ridge attributes\n");
121 }
122out:
123 kfree(rs->buffer);
124 rs->buffer = NULL;
125 return ret;
126}
127
128/*
129 * We think there's a record of type `sig' at rs->chr. Parse the signature
130 * and make sure that there's really room for a record of that type.
131 */
132static int rock_check_overflow(struct rock_state *rs, int sig)
133{
134 int len;
135
136 switch (sig) {
137 case SIG('S', 'P'):
138 len = sizeof(struct SU_SP_s);
139 break;
140 case SIG('C', 'E'):
141 len = sizeof(struct SU_CE_s);
142 break;
143 case SIG('E', 'R'):
144 len = sizeof(struct SU_ER_s);
145 break;
146 case SIG('R', 'R'):
147 len = sizeof(struct RR_RR_s);
148 break;
149 case SIG('P', 'X'):
150 len = sizeof(struct RR_PX_s);
151 break;
152 case SIG('P', 'N'):
153 len = sizeof(struct RR_PN_s);
154 break;
155 case SIG('S', 'L'):
156 len = sizeof(struct RR_SL_s);
157 break;
158 case SIG('N', 'M'):
159 len = sizeof(struct RR_NM_s);
160 break;
161 case SIG('C', 'L'):
162 len = sizeof(struct RR_CL_s);
163 break;
164 case SIG('P', 'L'):
165 len = sizeof(struct RR_PL_s);
166 break;
167 case SIG('T', 'F'):
168 len = sizeof(struct RR_TF_s);
169 break;
170 case SIG('Z', 'F'):
171 len = sizeof(struct RR_ZF_s);
172 break;
173 default:
174 len = 0;
175 break;
176 }
177 len += offsetof(struct rock_ridge, u);
178 if (len > rs->len) {
179 printk(KERN_NOTICE "rock: directory entry would overflow "
180 "storage\n");
181 printk(KERN_NOTICE "rock: sig=0x%02x, size=%d, remaining=%d\n",
182 sig, len, rs->len);
183 return -EIO;
184 }
185 return 0;
186}
187
188/*
189 * return length of name field; 0: not found, -1: to be ignored
190 */
191int get_rock_ridge_filename(struct iso_directory_record *de,
192 char *retname, struct inode *inode)
193{
194 struct rock_state rs;
195 struct rock_ridge *rr;
196 int sig;
197 int retnamlen = 0;
198 int truncate = 0;
199 int ret = 0;
200
201 if (!ISOFS_SB(inode->i_sb)->s_rock)
202 return 0;
203 *retname = 0;
204
205 init_rock_state(&rs, inode);
206 setup_rock_ridge(de, inode, &rs);
207repeat:
208
209 while (rs.len > 2) { /* There may be one byte for padding somewhere */
210 rr = (struct rock_ridge *)rs.chr;
211 /*
212 * Ignore rock ridge info if rr->len is out of range, but
213 * don't return -EIO because that would make the file
214 * invisible.
215 */
216 if (rr->len < 3)
217 goto out; /* Something got screwed up here */
218 sig = isonum_721(rs.chr);
219 if (rock_check_overflow(&rs, sig))
220 goto eio;
221 rs.chr += rr->len;
222 rs.len -= rr->len;
223 /*
224 * As above, just ignore the rock ridge info if rr->len
225 * is bogus.
226 */
227 if (rs.len < 0)
228 goto out; /* Something got screwed up here */
229
230 switch (sig) {
231 case SIG('R', 'R'):
232 if ((rr->u.RR.flags[0] & RR_NM) == 0)
233 goto out;
234 break;
235 case SIG('S', 'P'):
236 if (check_sp(rr, inode))
237 goto out;
238 break;
239 case SIG('C', 'E'):
240 rs.cont_extent = isonum_733(rr->u.CE.extent);
241 rs.cont_offset = isonum_733(rr->u.CE.offset);
242 rs.cont_size = isonum_733(rr->u.CE.size);
243 break;
244 case SIG('N', 'M'):
245 if (truncate)
246 break;
247 if (rr->len < 5)
248 break;
249 /*
250 * If the flags are 2 or 4, this indicates '.' or '..'.
251 * We don't want to do anything with this, because it
252 * screws up the code that calls us. We don't really
253 * care anyways, since we can just use the non-RR
254 * name.
255 */
256 if (rr->u.NM.flags & 6)
257 break;
258
259 if (rr->u.NM.flags & ~1) {
260 printk("Unsupported NM flag settings (%d)\n",
261 rr->u.NM.flags);
262 break;
263 }
264 if ((strlen(retname) + rr->len - 5) >= 254) {
265 truncate = 1;
266 break;
267 }
268 strncat(retname, rr->u.NM.name, rr->len - 5);
269 retnamlen += rr->len - 5;
270 break;
271 case SIG('R', 'E'):
272 kfree(rs.buffer);
273 return -1;
274 default:
275 break;
276 }
277 }
278 ret = rock_continue(&rs);
279 if (ret == 0)
280 goto repeat;
281 if (ret == 1)
282 return retnamlen; /* If 0, this file did not have a NM field */
283out:
284 kfree(rs.buffer);
285 return ret;
286eio:
287 ret = -EIO;
288 goto out;
289}
290
291static int
292parse_rock_ridge_inode_internal(struct iso_directory_record *de,
293 struct inode *inode, int regard_xa)
294{
295 int symlink_len = 0;
296 int cnt, sig;
297 struct inode *reloc;
298 struct rock_ridge *rr;
299 int rootflag;
300 struct rock_state rs;
301 int ret = 0;
302
303 if (!ISOFS_SB(inode->i_sb)->s_rock)
304 return 0;
305
306 init_rock_state(&rs, inode);
307 setup_rock_ridge(de, inode, &rs);
308 if (regard_xa) {
309 rs.chr += 14;
310 rs.len -= 14;
311 if (rs.len < 0)
312 rs.len = 0;
313 }
314
315repeat:
316 while (rs.len > 2) { /* There may be one byte for padding somewhere */
317 rr = (struct rock_ridge *)rs.chr;
318 /*
319 * Ignore rock ridge info if rr->len is out of range, but
320 * don't return -EIO because that would make the file
321 * invisible.
322 */
323 if (rr->len < 3)
324 goto out; /* Something got screwed up here */
325 sig = isonum_721(rs.chr);
326 if (rock_check_overflow(&rs, sig))
327 goto eio;
328 rs.chr += rr->len;
329 rs.len -= rr->len;
330 /*
331 * As above, just ignore the rock ridge info if rr->len
332 * is bogus.
333 */
334 if (rs.len < 0)
335 goto out; /* Something got screwed up here */
336
337 switch (sig) {
338#ifndef CONFIG_ZISOFS /* No flag for SF or ZF */
339 case SIG('R', 'R'):
340 if ((rr->u.RR.flags[0] &
341 (RR_PX | RR_TF | RR_SL | RR_CL)) == 0)
342 goto out;
343 break;
344#endif
345 case SIG('S', 'P'):
346 if (check_sp(rr, inode))
347 goto out;
348 break;
349 case SIG('C', 'E'):
350 rs.cont_extent = isonum_733(rr->u.CE.extent);
351 rs.cont_offset = isonum_733(rr->u.CE.offset);
352 rs.cont_size = isonum_733(rr->u.CE.size);
353 break;
354 case SIG('E', 'R'):
355 ISOFS_SB(inode->i_sb)->s_rock = 1;
356 printk(KERN_DEBUG "ISO 9660 Extensions: ");
357 {
358 int p;
359 for (p = 0; p < rr->u.ER.len_id; p++)
360 printk("%c", rr->u.ER.data[p]);
361 }
362 printk("\n");
363 break;
364 case SIG('P', 'X'):
365 inode->i_mode = isonum_733(rr->u.PX.mode);
366 set_nlink(inode, isonum_733(rr->u.PX.n_links));
367 inode->i_uid = isonum_733(rr->u.PX.uid);
368 inode->i_gid = isonum_733(rr->u.PX.gid);
369 break;
370 case SIG('P', 'N'):
371 {
372 int high, low;
373 high = isonum_733(rr->u.PN.dev_high);
374 low = isonum_733(rr->u.PN.dev_low);
375 /*
376 * The Rock Ridge standard specifies that if
377 * sizeof(dev_t) <= 4, then the high field is
378 * unused, and the device number is completely
379 * stored in the low field. Some writers may
380 * ignore this subtlety,
381 * and as a result we test to see if the entire
382 * device number is
383 * stored in the low field, and use that.
384 */
385 if ((low & ~0xff) && high == 0) {
386 inode->i_rdev =
387 MKDEV(low >> 8, low & 0xff);
388 } else {
389 inode->i_rdev =
390 MKDEV(high, low);
391 }
392 }
393 break;
394 case SIG('T', 'F'):
395 /*
396 * Some RRIP writers incorrectly place ctime in the
397 * TF_CREATE field. Try to handle this correctly for
398 * either case.
399 */
400 /* Rock ridge never appears on a High Sierra disk */
401 cnt = 0;
402 if (rr->u.TF.flags & TF_CREATE) {
403 inode->i_ctime.tv_sec =
404 iso_date(rr->u.TF.times[cnt++].time,
405 0);
406 inode->i_ctime.tv_nsec = 0;
407 }
408 if (rr->u.TF.flags & TF_MODIFY) {
409 inode->i_mtime.tv_sec =
410 iso_date(rr->u.TF.times[cnt++].time,
411 0);
412 inode->i_mtime.tv_nsec = 0;
413 }
414 if (rr->u.TF.flags & TF_ACCESS) {
415 inode->i_atime.tv_sec =
416 iso_date(rr->u.TF.times[cnt++].time,
417 0);
418 inode->i_atime.tv_nsec = 0;
419 }
420 if (rr->u.TF.flags & TF_ATTRIBUTES) {
421 inode->i_ctime.tv_sec =
422 iso_date(rr->u.TF.times[cnt++].time,
423 0);
424 inode->i_ctime.tv_nsec = 0;
425 }
426 break;
427 case SIG('S', 'L'):
428 {
429 int slen;
430 struct SL_component *slp;
431 struct SL_component *oldslp;
432 slen = rr->len - 5;
433 slp = &rr->u.SL.link;
434 inode->i_size = symlink_len;
435 while (slen > 1) {
436 rootflag = 0;
437 switch (slp->flags & ~1) {
438 case 0:
439 inode->i_size +=
440 slp->len;
441 break;
442 case 2:
443 inode->i_size += 1;
444 break;
445 case 4:
446 inode->i_size += 2;
447 break;
448 case 8:
449 rootflag = 1;
450 inode->i_size += 1;
451 break;
452 default:
453 printk("Symlink component flag "
454 "not implemented\n");
455 }
456 slen -= slp->len + 2;
457 oldslp = slp;
458 slp = (struct SL_component *)
459 (((char *)slp) + slp->len + 2);
460
461 if (slen < 2) {
462 if (((rr->u.SL.
463 flags & 1) != 0)
464 &&
465 ((oldslp->
466 flags & 1) == 0))
467 inode->i_size +=
468 1;
469 break;
470 }
471
472 /*
473 * If this component record isn't
474 * continued, then append a '/'.
475 */
476 if (!rootflag
477 && (oldslp->flags & 1) == 0)
478 inode->i_size += 1;
479 }
480 }
481 symlink_len = inode->i_size;
482 break;
483 case SIG('R', 'E'):
484 printk(KERN_WARNING "Attempt to read inode for "
485 "relocated directory\n");
486 goto out;
487 case SIG('C', 'L'):
488 ISOFS_I(inode)->i_first_extent =
489 isonum_733(rr->u.CL.location);
490 reloc =
491 isofs_iget(inode->i_sb,
492 ISOFS_I(inode)->i_first_extent,
493 0);
494 if (IS_ERR(reloc)) {
495 ret = PTR_ERR(reloc);
496 goto out;
497 }
498 inode->i_mode = reloc->i_mode;
499 set_nlink(inode, reloc->i_nlink);
500 inode->i_uid = reloc->i_uid;
501 inode->i_gid = reloc->i_gid;
502 inode->i_rdev = reloc->i_rdev;
503 inode->i_size = reloc->i_size;
504 inode->i_blocks = reloc->i_blocks;
505 inode->i_atime = reloc->i_atime;
506 inode->i_ctime = reloc->i_ctime;
507 inode->i_mtime = reloc->i_mtime;
508 iput(reloc);
509 break;
510#ifdef CONFIG_ZISOFS
511 case SIG('Z', 'F'): {
512 int algo;
513
514 if (ISOFS_SB(inode->i_sb)->s_nocompress)
515 break;
516 algo = isonum_721(rr->u.ZF.algorithm);
517 if (algo == SIG('p', 'z')) {
518 int block_shift =
519 isonum_711(&rr->u.ZF.parms[1]);
520 if (block_shift > 17) {
521 printk(KERN_WARNING "isofs: "
522 "Can't handle ZF block "
523 "size of 2^%d\n",
524 block_shift);
525 } else {
526 /*
527 * Note: we don't change
528 * i_blocks here
529 */
530 ISOFS_I(inode)->i_file_format =
531 isofs_file_compressed;
532 /*
533 * Parameters to compression
534 * algorithm (header size,
535 * block size)
536 */
537 ISOFS_I(inode)->i_format_parm[0] =
538 isonum_711(&rr->u.ZF.parms[0]);
539 ISOFS_I(inode)->i_format_parm[1] =
540 isonum_711(&rr->u.ZF.parms[1]);
541 inode->i_size =
542 isonum_733(rr->u.ZF.
543 real_size);
544 }
545 } else {
546 printk(KERN_WARNING
547 "isofs: Unknown ZF compression "
548 "algorithm: %c%c\n",
549 rr->u.ZF.algorithm[0],
550 rr->u.ZF.algorithm[1]);
551 }
552 break;
553 }
554#endif
555 default:
556 break;
557 }
558 }
559 ret = rock_continue(&rs);
560 if (ret == 0)
561 goto repeat;
562 if (ret == 1)
563 ret = 0;
564out:
565 kfree(rs.buffer);
566 return ret;
567eio:
568 ret = -EIO;
569 goto out;
570}
571
572static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
573{
574 int slen;
575 int rootflag;
576 struct SL_component *oldslp;
577 struct SL_component *slp;
578 slen = rr->len - 5;
579 slp = &rr->u.SL.link;
580 while (slen > 1) {
581 rootflag = 0;
582 switch (slp->flags & ~1) {
583 case 0:
584 if (slp->len > plimit - rpnt)
585 return NULL;
586 memcpy(rpnt, slp->text, slp->len);
587 rpnt += slp->len;
588 break;
589 case 2:
590 if (rpnt >= plimit)
591 return NULL;
592 *rpnt++ = '.';
593 break;
594 case 4:
595 if (2 > plimit - rpnt)
596 return NULL;
597 *rpnt++ = '.';
598 *rpnt++ = '.';
599 break;
600 case 8:
601 if (rpnt >= plimit)
602 return NULL;
603 rootflag = 1;
604 *rpnt++ = '/';
605 break;
606 default:
607 printk("Symlink component flag not implemented (%d)\n",
608 slp->flags);
609 }
610 slen -= slp->len + 2;
611 oldslp = slp;
612 slp = (struct SL_component *)((char *)slp + slp->len + 2);
613
614 if (slen < 2) {
615 /*
616 * If there is another SL record, and this component
617 * record isn't continued, then add a slash.
618 */
619 if ((!rootflag) && (rr->u.SL.flags & 1) &&
620 !(oldslp->flags & 1)) {
621 if (rpnt >= plimit)
622 return NULL;
623 *rpnt++ = '/';
624 }
625 break;
626 }
627
628 /*
629 * If this component record isn't continued, then append a '/'.
630 */
631 if (!rootflag && !(oldslp->flags & 1)) {
632 if (rpnt >= plimit)
633 return NULL;
634 *rpnt++ = '/';
635 }
636 }
637 return rpnt;
638}
639
640int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode)
641{
642 int result = parse_rock_ridge_inode_internal(de, inode, 0);
643
644 /*
645 * if rockridge flag was reset and we didn't look for attributes
646 * behind eventual XA attributes, have a look there
647 */
648 if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1)
649 && (ISOFS_SB(inode->i_sb)->s_rock == 2)) {
650 result = parse_rock_ridge_inode_internal(de, inode, 14);
651 }
652 return result;
653}
654
655/*
656 * readpage() for symlinks: reads symlink contents into the page and either
657 * makes it uptodate and returns 0 or returns error (-EIO)
658 */
659static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
660{
661 struct inode *inode = page->mapping->host;
662 struct iso_inode_info *ei = ISOFS_I(inode);
663 struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
664 char *link = kmap(page);
665 unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
666 struct buffer_head *bh;
667 char *rpnt = link;
668 unsigned char *pnt;
669 struct iso_directory_record *raw_de;
670 unsigned long block, offset;
671 int sig;
672 struct rock_ridge *rr;
673 struct rock_state rs;
674 int ret;
675
676 if (!sbi->s_rock)
677 goto error;
678
679 init_rock_state(&rs, inode);
680 block = ei->i_iget5_block;
681 bh = sb_bread(inode->i_sb, block);
682 if (!bh)
683 goto out_noread;
684
685 offset = ei->i_iget5_offset;
686 pnt = (unsigned char *)bh->b_data + offset;
687
688 raw_de = (struct iso_directory_record *)pnt;
689
690 /*
691 * If we go past the end of the buffer, there is some sort of error.
692 */
693 if (offset + *pnt > bufsize)
694 goto out_bad_span;
695
696 /*
697 * Now test for possible Rock Ridge extensions which will override
698 * some of these numbers in the inode structure.
699 */
700
701 setup_rock_ridge(raw_de, inode, &rs);
702
703repeat:
704 while (rs.len > 2) { /* There may be one byte for padding somewhere */
705 rr = (struct rock_ridge *)rs.chr;
706 if (rr->len < 3)
707 goto out; /* Something got screwed up here */
708 sig = isonum_721(rs.chr);
709 if (rock_check_overflow(&rs, sig))
710 goto out;
711 rs.chr += rr->len;
712 rs.len -= rr->len;
713 if (rs.len < 0)
714 goto out; /* corrupted isofs */
715
716 switch (sig) {
717 case SIG('R', 'R'):
718 if ((rr->u.RR.flags[0] & RR_SL) == 0)
719 goto out;
720 break;
721 case SIG('S', 'P'):
722 if (check_sp(rr, inode))
723 goto out;
724 break;
725 case SIG('S', 'L'):
726 rpnt = get_symlink_chunk(rpnt, rr,
727 link + (PAGE_SIZE - 1));
728 if (rpnt == NULL)
729 goto out;
730 break;
731 case SIG('C', 'E'):
732 /* This tells is if there is a continuation record */
733 rs.cont_extent = isonum_733(rr->u.CE.extent);
734 rs.cont_offset = isonum_733(rr->u.CE.offset);
735 rs.cont_size = isonum_733(rr->u.CE.size);
736 default:
737 break;
738 }
739 }
740 ret = rock_continue(&rs);
741 if (ret == 0)
742 goto repeat;
743 if (ret < 0)
744 goto fail;
745
746 if (rpnt == link)
747 goto fail;
748 brelse(bh);
749 *rpnt = '\0';
750 SetPageUptodate(page);
751 kunmap(page);
752 unlock_page(page);
753 return 0;
754
755 /* error exit from macro */
756out:
757 kfree(rs.buffer);
758 goto fail;
759out_noread:
760 printk("unable to read i-node block");
761 goto fail;
762out_bad_span:
763 printk("symlink spans iso9660 blocks\n");
764fail:
765 brelse(bh);
766error:
767 SetPageError(page);
768 kunmap(page);
769 unlock_page(page);
770 return -EIO;
771}
772
773const struct address_space_operations isofs_symlink_aops = {
774 .readpage = rock_ridge_symlink_readpage
775};